Paint Blistering

Definition: Lifting of the paint film from the underlying surface, which appears as bubbles or blisters in the paint, usually caused by heat, moisture or a combination of both. This condition can eventually lead to peeling of the paint if not corrected. This is called Paint Blistering.

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Causes:

Painting in direct sunlight or on a surface that is too hot

Application of an oil-based or alkyd paint over a damp, wet surface

Exposing a fresh paint film to dew, high humidity or rain

Moisture passing through interior walls from common household sources such as bathrooms, kitchens and laundry rooms causes paint blistering.

Solutions:

Determine if blisters were caused by heat or moisture. Break open and examine the substrate and back side of blistered paint.

If only the newest coat of paint is blistered, the blister was probably caused by heat.

If the peeled blister contains several coats of paint and the bare surface is exposed, the blister was probably caused by moisture.

For paint blistering caused by heat

Remove blisters by scraping, sanding or pressure-washing down to underlying coats of paint or primer.